On 11/15/2016 07:21 AM, anonymous anonymous wrote: > Thank you so much for the extense answer! > > It happens that the person who analysed the first measure (of this > longitudinal dataset) used two different OS (he did it in a Virtual > machine on windows and a mac OS X) to speed up this step. That data has > already been used in some studies. > > > ¿So my question now would be how much does that really affect to the > results?
It is impossible to know for sure without processing the results on the same OS. My guess is quite small, generally we see results differ on the order of 5% or less, but still potentially enough to introduce bias. > > > > > > > >> Hi >> >> I am using recon-all in some longitudinal data on a ubuntu 16.04, and >> using >> the development version of freesurfer as I was told here, because the >> other >> current version doesnt work on ubuntu 16.04. >> >> The problem is that the first scans were probablly processed using >> virtualbox in a windows and an older version of freesurfer. >> >> >> i think I already know the answer, that I can't do this if I dont want to >> bias my results. Can I? > > Yup. You know the answer ;) However, I did discover a way to make > freesurfer 5.3 work on Ubuntu 16 by doing the following steps to install > an older version of perl : > > 1) install perlbrew: > > $> sudo apt-get install perlbrew > > 2) use perlbrew to install perl version 5.20.3: > > $> perlbrew install perl-5.20.3 > > 3) You must change the '/bin/perl' file to a link which points to the > version of perl installed by perlbrew. (This technique is not the > standard practice but it is the only way to get the mni tools to use the > older version of perl): > > $> cd /bin > $> sudo mv perl perl.orig (can always set back later) > $> ln -s ~/perl5/perlbrew/perls/perl-5.20.3/bin/perl > > >> >> But I'm using a better computer now and I use the one with windows for >> other analyses, so I wanted to know if I could install Virtual box on my >> ubuntu 16.04 computer, and install the same version of linux used to >> process the first measure. Should I also need to use the same version of >> freesurfer? > > > You could do that, but The Virtual Box version is not really good for > processing a large number of subjects because of the limited amount of > disk space on the virtual image. Its really meant more as a teaching tool > for users with Windows machines. > >> >> f the computer's specs are dfferent, does it matter? And if I assign >> different cpu and ram on my virtual machine? > > Different specs are fine. Its the OS, OS version, and version of > freesurfer that should stay the same. > > >> >> Thank you! >> _______________________________________________ >> Freesurfer mailing list >> Freesurfer@nmr.mgh.harvard.edu <mailto:Freesurfer@nmr.mgh.harvard.edu> >> https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > <https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer> > > _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail.
